Hi, The below latency stats RFC adds new field to second cache line of mbuf. This is not an ABI break. But I would like to emphasize on this point so you can have a look into the changes and provide comments.
Thanks, Reshma > -----Original Message----- > From: Pattan, Reshma > Sent: Monday, October 17, 2016 2:40 PM > To: dev at dpdk.org > Cc: Pattan, Reshma <reshma.pattan at intel.com> > Subject: [RFC v3] latencystats: added new library for latency stats > > Library is designed to calculate latency stats and report them to the > application > when queried. Library measures minimum, average, maximum latencies and > jitter in nano seconds. > Current implementation supports global latency stats, i.e. per application > stats. > > Added new field to mbuf struct to mark the packet arrival time on Rx and use > the > times tamp to measure the latency on Tx. > > Modified dpdk-procinfo process to display the new stats. > > APIs: > > Added APIs to initialize and un initialize latency stats calculation. > Added API to retrieve latency stats names and values. > > Functionality: > > *Library will register ethdev Rx/Tx callbacks for each active port, queue > combinations. > *Library will register latency stats names with new stats library, which is > under > design for now. > *Rx packets will be marked with time stamp on each sampling interval. > *On Tx side, packets with time stamp will be considered for calculating the > minimum, maximum, average latencies and jitter. > *Average latency is calculated by summing all the latencies measured for each > time stamped packet and dividing that by total time stamped packets. > *Minimum and maximum latencies will be low and high latency values observed > so far. > *Jitter calculation is done based on inter packet delay variation. > *Measured stats can be retrieved via get API of the libray (or) by calling > generic > get API of the new stats library, in this case callback is provided to update > the > stats into new stats library. > > Signed-off-by: Reshma Pattan <reshma.pattan at intel.com>
